Scraper-chain conveyors are frequently used, in particular, in mining as face or gate conveyors and also for debris haulage during tunnel driving. The scraper-chain assembly of the conveyor, typically designed as a centre-strand assembly, is driven continuously through one or two chains connected to spaced-apart scrapers moving along in upper and lower runs in the central region of the conveyor troughs or pans. The scraper-chain assembly is entrained around chain drums which are mounted in machine frames arranged on the conveyor troughs at the ends of the conveyor. The chain drum at the discharge end of the conveyor is usually driven by a main conveyor drive flanged laterally on the machine frame to form a drive station. At the other end of the conveyor, the drum forms a reversing station which can comprise a further (auxiliary) drive, but can frequently also be without a drive, in particular in the case of conveyors with relatively small lengths.
During operation, the chain drums of these arrangements are exposed to very high stresses and therefore wear rapidly. In particular, the sprocket wheels which mesh with the chain or chains wear very rapidly so it is necessary to design the chain drums in such a way that they can easily be removed and exchanged whenever necessary.
A known chain drum arrangement disclosed in DE-OS 42 04 381 has a chain drum which together with its short stub shaft, can be removed from the drive assembly after the release of screw bolts placed transversely through the shaft and holding the drum arrangement in the machine frame. With this arrangement, therefore, the chain drum is always exchanged together with its shaft, and this constructional unit is comparatively heavy and correspondingly difficult to handle. The arrangement has the further drawback that it necessitates time-consuming alterations if only the chain drum is to be replaced by a new one and the chain drum shaft with its bearing is to be retained.
With a chain drum arrangement known from DE-AS 1 756 355, the chain drum can also be removed together with its shaft and the rolling bearings arranged thereon from the machine frame. For this purpose, the rolling bearings are received in the machine with divided carrying rings. One ring half has to be dismantled and removed from each bearing before the drum arrangement can be exchanged. The use of divided carrying rings is disadvantageous in view of the high load stresses which tends to cause premature wear of the bearing carrying rings. The unit composed of the drum, shaft and bearings is also subject to the same disadvantages as described hereinbefore with respect to the high weight of the unit which is to be exchanged and the additional assembly cost for exchanging the bearings in the dismantled state of the chain drum.
DE-OS 195 47 351 discloses a drive station for scraper-chain conveyors with a chain drum coupled to two drive shafts mounted in the machine frame. The chain drum shafts are mounted axially displaceably in the machine frame. At their leading ends projecting from the machine frame, the shafts have teeth with which they engage in an internal bore, provided with mating internal teeth, at the respective end face of the chain drum. For unlocking, the chain drum shafts are displaced axially in the machine frame so that the shaft ends engaging in the chain drum during operation are removed from the internal bore and are moved back into the machine frame so the entire chain drum can then be removed from the machine frame transversely to its axis. Although this known arrangement allows very simple and quick exchange of the chain drum, the displaceable mounting of the chain drum shafts is comparatively complicated and therefore expensive and susceptible to breakdown.